1. Field of the Invention
The present invention is related to an imaging apparatus such as electronic camera capable of storing images picked up by an image pickup device in an integrated memory or in an outside memory, particularly to an imaging apparatus such as an electronic camera in which an operation unit provided with a display is hinged to an imaging unit to which a high magnification optical zooming system is mounted so that the operation unit is rotatable relative to the imaging unit and which is constructed as a small-sized, low-profile, light weight, and user-friendly camera.
2. Description of the Related Art
With an electronic camera provided with an image pickup device such as a CCD and capable of memorizing images as digital data, pictures photographed can be seen immediately without developing, printing, etc. An image pickup devices such as a CCD is becoming smaller-sized than a film roll year by year in spite of increasing number of pixels per image, so there is an advantage in an electronic camera that the camera itself can be constructed in small size and with high precision.
An electric camera is desired which is, for example, thin in thickness and has enough strength so that it can be accommodated in the breast pocket of one's shirt or in the back pocket of one's pants and is light weighted so that it does not cause uncomfortable feeling even if it is accommodated in such a place as mentioned above or in a handbag and furthermore is provided with a high magnification zooming mechanism.
However, when an electronic camera is constructed such that the lens unit is protruded from the camera body as is the case with a conventional camera using a rolled film, it is difficult to make the thickness of the camera thinner than a certain thickness because of the zooming mechanism and thickness of the lens unit even in the case of a lens unit sinking type camera.
A zoom lens is composed such that one or more groups of lenses among a plurality of groups of lenses disposed on an optical axis are moved along the optical axis to change the focal distance of the zoom lens. As a means to move the lens group or groups when zooming, generally a cam plate is provided to be engaged with the lens group or groups, and the lens group or groups are moved according to the cam shape by moving or rotating the cam plate by hand or by means of a motor, etc. in order to move the lens group or groups under correlation between two or more of the lens groups.
As a cam mechanism of this kind, there is conventionally a mechanism in which a ring-shaped cam(hereafter referred to as a cam ring) is fit coaxially on the outer circumference of the lens-barrel, the lens groups are engaged with the ring cam, and the lens groups are moved by rotating the ring cam around the axis of the lens-barrel. There is also a zooming mechanism in which a lead screw is provided along the optical axis of the lens-barrel, the lens group or groups to be moved are screwed into the lead screw, and the lens group or groups screwed in the lead screw is moved in the direction of the optical axis by rotating the lead screw by means of a motor, etc.
Therefore, it is impossible to compose the camera body thinner in the direction of optical axis than the height of the ring cam or the sum of the thickness of each of a plurality of lenses when the lenses are disposed in the front part of the camera body and the cam ring is fit on the circumference of the lens-barrel as mentioned above, even if it is composed so that all the lenses can be drew back into the camera body by switching off electric source to leave no protruding part remained in the front of the camera body. Further, the zoom lens consists of a plurality of lens groups as mentioned above, so the number of lenses increases with increased magnification, the sum of the thickness of lenses becomes fairly large, and it is difficult to compose a camera small in thickness
Also, there is a problem that when the cam ring is provided on the outer circumference of the lens-barrel, the diameter of the lens unit becomes large resulting in an increased size of camera, which is an impeding factor for designing a low-profile camera.
However, there has appeared a camera having structure with which the increase in the thickness of camera with increased magnification is suppressed.
For example, in a lens unit sinking type camera in which a plurality of lenses are accommodated in the camera body when not photographing, a structure is adopted in which when the main electric source is shut off to accommodate the protruded lens groups in the body, lens group A located near intermediate position among a plurality of lens groups to be moved along the optical axis is moved off to a range outside the optical axis range to be accommodated in the camera body. Lens group B located in a position toward subject side from the intermediate position is accommodated in the camera body in the optical axis range.
Therefore, the thickness of the camera in the direction of the optical axis can be reduced by moving lens group A located near intermediate position to a range outside the optical axis range.
However, in the camera composed to move the lens group located near the intermediate position to the range outside the optical axis range, the structure is complicated for securing accuracies of optical groups as the lens groups must be moved off to the range outside the optical axis range, and the number of component parts increases for moving off the lens groups to the range outside the optical axis range, resulting in an increase in manufacturing cost.
Further, with a camera in which intermediate lens groups or lens-barrel is immersed in the camera body by switching off the main electric source, it takes a certain time until shooting pictures becomes possible because it takes a certain time until the lens groups are protruded after the main electric source is switched on, and photo opportunity may be missed.
With a camera in which a lead screw is provided along the optical axis of the lens-barrel, the number of component parts can be reduced by eliminating the cam ring, etc. resulting in a reduction in space near the lens-barrel compared with the case the cam mechanism is used, and weight saving of the camera is possible.
As to zooming mechanism, as disclosed in Japanese Laid-Open Patent Application No. 4-158682 and No. 7-23259 for example, it is thinkable to compose such that the optical axis is determined in a longer side or shorter side direction of a pocket notebook type camera which is provided with a display on its foldable cover, a window for taking pictures is provided in the lower side of the camera body, the light incoming through the window is reflected by a reflecting mirror disposed to incline at 45° to the window to be launched into the lens groups of which the optical axis is directed in a longer side or shorter side direction of the camera body, and the reflected light is again reflected by a reflecting mirror disposed to incline at 45° to the optical axis to be launched into an image pickup device disposed parallel to the optical axis (see Japanese Laid-Open Patent Application No. 4-158682) or such that a display is provided on one flat face of an pocket notebook type camera, a window is provided in the side face of the camera body, lens groups are disposed in the camera body with its optical axis directed in a longitudinal direction of the camera body (see Japanese Laid-Open Patent Application No. 7-23259), thus the full length of optical group is accommodated in the camera body.
However, generally this type of camera is provided with a plurality of lenses parallel to the display for displaying images photographed or to be photographed, reflectors or prisms are provided between the lenses behind the first lens to face the subject to be shot to change the light axis by 90°, and the subject is shot with the face of the display directed in the direction parallel to the direction toward the subject. With this composition, the number of component parts is reduced and downsizing of camera can be achieved, on the other hand, reflectors or prisms are necessary and the structure becomes complicated, which results in an increase in weight and cost, so downsizing or low-profiling compared to the case of a camera provided with a cam mechanism is not conspicuous.
A camera is proposed in Japanese Laid-Open Patent Application No. 11-261859 and No. 2002-320120, in which an imaging unit provided with a set of lenses, a finder, a light emitting apparatus, etc. is connected rotatably by a rotation mechanism such as a hinge mechanism to an operation unit provided with a display in order to make it possible to direct the imaging unit to a subject to be shot by rotating it with the display directed to the user. With this composition of an electric camera, the user can check the image on the display while directing the imaging unit to the subject even when the subject is the user him-or-herself or a subject near the ground.
In Japanese Patent No. 2931907 is disclosed a camera, in which an imaging unit provided with lenses, an image pickup device, and light emitting apparatus is connected rotatably to a camera body provided with a display such as a liquid crystal, the imaging unit can be turned to be directed to a subject to be photographed while directing the display to the user when taking pictures, and the imaging unit is turned to the position with which the unit is parallel to the display to be accommodated in the camera body when not shooting. By this construction, a reduction in the thickness in the direction perpendicular to the display of the camera body is achieved.
However, with a camera such as disclosed in Japanese Laid-Open Patent Application No. 4-158682 or No. 7-23259, there is a problem in addition to the problem mentioned above that, although it is possible to see the display when the window for taking pictures is directed to a subject to be shot at the level of user's eyes, it is difficult to check the coverage of picture on the display when shooting the user him-or-herself or a subject near the ground or over the heads of a crowd because the display is disposed on the opposite side of the window for taking pictures, and the user has no choice but to shoot by the seat of his pants. The camera disclosed in Japanese Laid-Open Patent Application No. 7-23259 is composed such that the surface of the display is parallel to the light axis, so when shooting with the camera held at the level of user's eyes, the user can check the coverage of picture on the display, but it is difficult to check the coverage of picture on the display when shooting with the camera held at the position lower than the level of user's eyes.
The camera disclosed in Japanese Laid-Open Patent Application No. 11-261859 or No. 2002-320120 is of a structure in which the operation unit and imaging unit is divided along the shorter side direction, so the image displaying plane area is inevitably small, and when this type of camera is composed to be a low-profile camera(thin-model camera), operation buttons protrude on the flat surface of the camera in addition to that the rigidity of the camera is reduced. Further, as the battery housing portion of the operation unit is thick compared with other portions and it becomes a grip portion. Due to the operation buttons and grip portions, it is difficult to get the camera in and out of the breast pocket of one's shirt or back pocket of one's pants smoothly.
Further, in the camera, although the zoom button is positioned on the same plane as the display, shutter release button and other operation buttons and command dials are positioned on the surface of the camera. Therefore, the operation buttons and command dials can not be operated by a user's thumb but need to be operated by his forefinger or other fingers, and further to operate those buttons while viewing the display is not possible.
With the camera disclosed in Japanese Laid-Open Patent Application No. 11-261859 or No. 2002-320120, if the photographed image on the display is held always in the same state thereon, a vertically inverted image is displayed on the display when the lens and the display is turned to face toward the user in order to shoot him-or-herself while checking the image to be shot on the display.
Further, the camera disclosed in Japanese Patent No. 2931907 is also composed such that the operation unit accounts for a large portion of the whole of the camera, a recess is formed in the front side of the operation unit for accommodating the imaging unit in order to secure a large display area, and the imaging unit can be accommodated rotatably in the recess, so that, although the downsizing of the camera can be achieved, whole camera body becomes too thick to be capable of being accommodated in the breast pocket of one's shirt or back pocket of one's pants.
Further, with the electronic camera composed such that the imaging unit integrating the lens and image pickup device is rotatable relative to the camera body provided with the display as disclosed in said Japanese Patent No. 2931907, it is possible to shoot the user him-or-herself by rotating the imaging unit toward the user (hereafter, this shooting is referred to as self-portrait shooting), however, when practicing self-portrait shooting, the user him-or-herself carries the camera and object distance is limited within 1 m. Therefore, the image of the user him-or-herself is displayed on the display as a large image and magnification should be adjusted each time of self-portrait shooting.
With the camera with a zoom lens like this, the zoom lens may be deteriorated in precision by a vibration caused by carrying around the camera, but if this happens, it is possible that the zoom lens is reset to eliminate the deterioration in precision by allowing it to return to initial setting when the lens is drawn back in the camera body by switching off the electric source in the case of a lens unit sinking type camera. However, with a camera of which the lens is drawn back when not shooting, a certain time is necessary before shooting is ready after the electric source is switched on, that is, start-up time is long, and it may happen to lose photo opportunity.
Further, with the electronic camera composed such that the camera is divided into an operation unit provided with the display and an imaging unit provided with a zoom lens, and the whole length of the optical system does not change when focal distance is changed by composing so that both the units are connected to be rotatable relatively to each other as mentioned above, start-up time after the electric source is switched on can be reduced because the zoom lens can be held in the state of focal distance as when last shooting was practiced. However, when deterioration in precision in the zoom lens is caused by vibration, the zoom lens is not reset and there may happen that the image of photograph is deteriorated.